Keep the actual dimensions
The selected retailer gives 23×31 cm and an approximate 9×12 inch size description. ISO A 4 is 210×297mm. These are different dimensions. A marketing shorthand or an approximate imperial conversion must not replace the selected metric record.
Fit a purchase brief precisely
If a class, folder or mount requires A 4, check the exact dimensions rather than assuming any medium rectangular pad qualifies. A 23×31 cm sheet may need trimming for a different requirement. The site does not invent a usable margin or assert that an unmeasured cover dimension equals the sheet dimension.
An area calculation with limits
From the declared sheet dimensions, 23×31 cm equals 713square centimetres or 0.0713square metres per sheet. Twelve declared sheets give 0.8556square metres of nominal one-face area. That does not establish useful painting coverage, trim yield or the amount of paint required.
Next decision
Use exact dimensions for an already defined requirement and ask the seller if the listing is ambiguous. No received measurements or tolerance test has been carried out. Approximate inch wording and a precise ISO label should remain separate fields rather than silently reconciled.
Sources & scope
Checked November 5, 2026. Manufacturer and retailer references support the specific statements. Dated displayed prices are not final checkout quotes, performance rankings or performance testing. This shopping reference does not replace the exact product label or retailer instructions. Current received labels and independent art-material/chemical/content/commerce review remain pending.
Keep reading
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